From 3d45262ebb951ec1f0d0eebfde154b76d31473aa Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marcel=20M=C3=A4rtens?= <marcel.cochem@googlemail.com>
Date: Mon, 22 Mar 2021 14:26:05 +0100
Subject: [PATCH] warn when a single system takes longer than 500ms

---
 common/ecs/src/system.rs | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/common/ecs/src/system.rs b/common/ecs/src/system.rs
index f1459967f4..dc7bb03fbc 100644
--- a/common/ecs/src/system.rs
+++ b/common/ecs/src/system.rs
@@ -74,7 +74,11 @@ impl CpuTimeline {
     /// this statement, till the next / end of the System.
     pub fn measure(&mut self, par: ParMode) { self.measures.push((Instant::now(), par)); }
 
-    fn end(&mut self) { self.measures.push((Instant::now(), ParMode::None)); }
+    fn end(&mut self) -> std::time::Duration {
+        let end = Instant::now();
+        self.measures.push((end, ParMode::None));
+        end.duration_since(self.measures.first().unwrap().0)
+    }
 
     fn get(&self, time: Instant) -> ParMode {
         match self.measures.binary_search_by_key(&time, |&(a, _)| a) {
@@ -254,7 +258,11 @@ where
         common_base::span!(_guard, "run", &format!("{}::Sys::run", T::NAME));
         self.cpu_stats.reset();
         T::run(self, data.0);
-        self.cpu_stats.end();
+        let millis = self.cpu_stats.end().as_millis();
+        let name = T::NAME;
+        if millis > 500 {
+            tracing::warn!(?millis, ?name, "slow system execution");
+        }
         data.1
             .stats
             .lock()